A 12MB L3 Cache: 50% Larger, 14% Higher Latency

Gulftown sticks to Ronak’s 2MB of L3 per core rule and has a full, 12MB shared L3 cache that’s accessible by any or all of the six cores. It’s actually because of the large unified L3 cache that performance in applications that don’t use all six cores can be higher than quad-core Core i7s.

Nehalem

Gulftown

The added cache does come at the expense of higher access latency. Nehalem and Lynnfield had a 42-cycle 8MB L3, Gulftown has a 48 cycle 12MB L3. A 14% higher latency for a 50% increase in size. Not an insignificant penalty, but a tradeoff that makes sense.

Identical Power Consumption to the Core i7 975

Raja has been busy with his DC clamp meter measuring actual power consumption of CPUs themselves rather than measuring power consumption at the wall. The results below compare the actual power draw of the 32nm Core i7 980X to the 45nm Core i7 975. These values are just the CPU itself, the rest of the system is completely removed from the equation:

CPU

Intel Core i7 980X

Intel Core i7 975

Idle

6.3W

6.3W

Load

136.8W

133.2W

Thanks to power gating, both of these chips idle at 6.3W. That's ridiculous for a 1.17B transistor chip. Under full load, the two are virtually identical - both drawing around 136W.

Westmere Goodness

The Core i7 980X is the first LGA-1366 processor based on Intel’s Westmere architecture, but unlike Clarkdale it does not have an on-die PCIe controller or on-package graphics. If anything, Gulftown really looks like a 6-core, 32nm version of Bloomfield rather than a scaled up Clarkdale. The similarities to Bloomfield extend all the way to the memory controller. Gulftown only officially supports three channels of DDR3-1066 memory, not 1333MHz like Lynnfield or Clarkdale. Of course running DDR3-1333 memory is possible, but the memory controller is technically operating out of spec at that frequency.

The processor does retain the Westmere specific features. The first Core i7 did not power gate its L3 cache, Lynnfield added it and Gulftown has it as well. While Mainly improved power efficiency and AES-NI instructions. I looked at the performance improvement offered by AES-NI acceleration in our Clarkdale review. If you use BitLocker or do a lot of archive encryption/decryption, you'll appreciate Gulftown's AES-NI.

Where did you get that information from? On intel website it says 1 QPI. from what I know and what always was the case all i7 series are single QPI's.THats why you have Xeon series with double QPI.Please do not post incorrect information, because people get stuck with expensive equipment not able to use it properly.Reply

Wondering how the i7 980X would do against a 6 core Opteron,Tech Report did some benchmark numbers when the 6 core Opterons (server) first came out,going head to head againt Xeons..interesting results when you compare the new i7. This is a rough estimate, but if AMD's 6 core is based on the 6 core Opteron this could be interesting..

Toms' has the PII X4 965 idling 21W lower than the 980X and 32W lower at load (using Prime95), however you have the 965 idling 10W HIGHER and using 4W more at load. Is Prime95 just favouring AMD or is there some sort of problem with your 790 rig? I will concede that the AMD rig will be using less RAM on the Toms' setup which may account for some of the difference.

One thing to note: up the resolution on a CPU-limited title such as Left4Dead and the performance gap narrows markedly. Enable AA and there's no difference at all. For graphically intensive games and/or highest settings, it won't make sense to fork out $1000 no matter how good the CPU.

It'd be nice to see how good this CPU is with multiple graphics cards... :) Reply